Embodiments of the present disclosure generally relate to methods and systems for determining a level of mechanical dyssynchrony in the heart.
A prevailing theory regarding response to cardiac resynchronization therapy (CRT) is that the therapy corrects mechanical dyssynchrony of the heart. Therefore, methods and systems have been proposed to accurately assess the dyssynchrony. The dyssynchrony information can be used to predict response to CRT as well as optimize LV lead placement and CRT programming parameters. Today, most methods to assess mechanical dyssynchrony involve echocardiography. However, in certain circumstances, conventional echocardiography techniques may experience errors that lead to inaccurate characterization of dyssynchrony. Further, questions still remain as to which specific approach(es) are preferred for assessing dyssynchrony, with various indices being used with mixed success.
Today, various cardiovascular navigation systems exist. For example, the St. Jude Medical MediGuide™ (MDG) cardiovascular navigation system is a 3-D electromagnetic navigation system that provides real-time position and orientation information regarding sensors embedded in electrophysiologic tools. The MDG system is integrated with a fluoroscopic (or other diagnostic) imaging system and tracks the sensors continuously within an imaging volume defined by the fluoroscopic system, on both live and recorded background diagnostic images.
Recently, it has been proposed to utilize the MDG system to characterize motion of the heart and to identify a desired (e.g., optimal) location for placement of a left ventricular (LV) lead. For example, the MDG system systematically records information associated with various endocardial and epicardial locations in the LV. Depending on the size of the heart and other factors during the procedure, there may be between 40 and 120 endocardial LV locations and/or a multitude of epicardial locations at which the MDG system obtains motion recordings for each patient. These recordings then need to be analyzed to characterize motion and mechanical activation patterns in the LV.
A need exists for methods and systems that utilize cardiovascular navigation systems for assessing mechanical dyssynchrony in connection with determining lead placement and programming parameters.